Mechanical transmission device

ABSTRACT

A linear actuator incorporates a casing on which a crank is mounted. Rotation of the crank produces rotation of a gear which meshes with the inner portion of a rotatably mounted ring. A cable is attached to the outer periphery of the ring and extends through a series of nested balls which engage a grooved portion of an arcuate teflon strip. The other end of the cable is attached to a rod which is slidably mounted in a stationary tube. Rotation of the crank produces a linear movement of the rod.

United States Patent Hacltman Nov. 13, 1973 [54] MECHANICAL TRANSMISSIONDEVICE 2,587,454 2/1952 Fletcher et al 74/501 R Inventor: Kenneth V.Hackman Arcadia 2,890,595 6/1959 Locffler 74/505 Calif. PrimaryExaminer-Charles J. Myhre [73] Assigneez fi/(Imthwest lgoldiu (10-,Assistant ExaminerF. D. Shoemaker Onmvld AtzorneyCharles G. Lyon et a1.[22] Filed: Mar. 20, 1972 [21] Appl. No.: 235,917 [57] ABSTRACT A linearactuator incorporates a casing on which a [52] 11.8. CI. 1. 74/505,74/501 R crank is mounted. Rotation of the crank produces ro- [51] Int.Cl. F16c 1/18 tation of a gear which meshes with the inner portion [58]Field of Search 74/501, 505; 287/78, ofa rotatably mounted ring. A cableis attached to the 287/76, 75 outer periphery of the ring and extendsthrough a series of nested balls which engage a grooved portion of [56]References Cited an arcuate teflon strip. The other end of the cable isUNITED STATES PATENTS attached to a rod which is slidably mounted in asta- 3 258 989 7/1966 Frese et al. 74/501 R tionary Rmatio of the CrankProduces a near 2,531,614 11/1950 De Pew 74 501 R movement 3,066,40412/1962 Jones 1 287/75 X 8 Cl 5 D F. 3,349,637 10/1967 Moore 1 74/501 Rrawmg gums 2,388,241 11/1945 Arens 74/501 R PATENTEUHUV 13 I973 SHEET10F 2 mum PATENIEUNUHB I915 3.771.384

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MECHANICAL TRANSMISSION DEVICE The present invention relates to animproved linear actuator.

An object of the present invention is to provide an improved linearactuator in which linear movement of a rod is accomplished upon rotationof a crank.

Another object of the present invention is to provide a linear actuatorusing a cable extending through a series of nested balls with improvedanti-friction means being provided for the balls to facilitate actuationand reduction of friction and for long life.

Another object of the present invention is to provide a linear actuatorwhich is relatively simple in construction and which may be easilyassembled and disassembled for manufacture, repair and replacementpurposes.

Another object of the present invention is to provide a linear actuatorcapable of transmitting large amounts of force with a construction thatis rugged, compact and easily operable.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. This inventionitself, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may be best understood byreference to the following description taken in connection with theaccompanying drawings in which:

FIG. 1 is a top plan view of a linear actuator embodying features of thepresent invention.

FIG. 2 is a sectional view taken substantially as indicated by the line22 in FIG. 1.

FIG. 3 is a sectional view taken substantially as indicated by the line3-3 in FIG. 2.

FIGS. 4 and 5 are sectional views taken substantially as indicated bythe corresponding lines 4-4 and 5-5 in FIG. 3.

The actuator assembly is intended to be mounted on a stationarystructure in three different locations, namely, at and by the bolt atand by the bolt 12; and at and by the shouldered collar 14A on the heavywall tube 14 through which the movable actuating rod 16 extends, thisrod 16 having a threaded portion 16A for attachment to an element (notshown) to be actuated, i.e., moved, linearly in or out of the stationarytube 14 upon manual rotation of the crank 18 using a construction nowdescribed in detail.

The crank 18 is rotatably mounted on a two-part housing which includes alower housing or casing member 22 cooperating with a complementary uppercasing member 24. These casing halves 22, 24 have aligned bushings 22A,24A through which the shaft 26 of crank 18 extends, such shaft 26 havingsecured thereto a gear 28 by means of pin 29. The casing halves 22, 24are maintained together using the previously mentioned bolts 10, 12.

The bolt is of special construction and includes an intermediateenlarged portion 10A serving as a shaft for the hub portion 30A of aring 30, such ring 30 being jointed to the hub portion 30A by tworadially extending arms or spiders 30B, 30C, such ring 30 having aportion of its inner circumference formed with gear teeth 30D which meshwith the previously mentioned crank-driven gear 28. The limitation ofmovement of the ring 30 is established by stop pins 40, 42 which aresecured as, for example, by screw threads to the base housing member 22.Stop 40 is engageable with the spider 308 in establishing one limit ofmovement, and the other stop post 42 is engageable with the other spider30C to establish the other limit of movement of ring 30.

This ring 30 has its outer periphery formed with a circumferentiallyextending grooved portion 30E and also with a recessed portion 30F forreception and attachment thereto of a series of nested balls 46 throughwhich a flexible cable 48 extends with one end of such cable 48 beingsecured to a threaded anchoring member 50, this member 50 being threadedin a nut 52 which has an integral portion 52A extending through anapertured portion of the ring 30 and being secured thereto by the nut528. The other end of the flexible cable 48 after passing throughcentral apertured portions of all of the nested balls 46 is secured to acylindrical element 54 which is slidably mounted in the heavy wall tube14 and which has one of its ends threaded at 54A for threaded connectionto the actuating rod 16.

The heavy wall tubing or sleeve 14 is stationarily secured to an outersleeve 60 using, for example, a knurled nut 62 having an internalshoulder portion 62A engaging a flanged portion 148 of the inner sleeve14. The outer sleeve 60, in turn, is secured to the casing halves 22,24, by the bolt 12 which as seen in FIG. 3 extends through a notchedportion of the outer sleeve 60.

An anti-friction element is incorporated in the assembly, and thisinvolves flexible strip of, for example, teflon material, such stripbeing disposed in a seat provided by the aligned undercut portions ofthe casing halves 22, 24, as seen in FIGS. 2 and 4. To facilitateassembly and establish position of the strip 70, three 10- cating pins80, 81, 82 (FIGS. 3 and 4) extend from the lower casing half 22 intoapertured portions of the strip 70. One end of the strip at 708terminates in a square shoulder, and the other end 70C terminates as atapered end to provide clearance for the tube 14 which, as seen in FIG.3, extends through the outer tube 60 and through the casing halves 22,24 into close proximity to the ring 30.

The series of balls 46 may either be hollow or solid construction andmay be of the character described in US. Pat. No. 2,441,719, issued May14, 1948 to Lee R. Potter.

The upper casing half 24 as seen in FIG. 1 is formed with a series ofradially extending notched portions 24E into one of which the conicalend of a locking screw 18E may extend, this screw 18E being threaded inthe handle 18 with a coil compresson spring 18F between the same forpurposes of locking the crank 18 to the casing 24 in those cases whereit is desired to prevent relative movement.

In operation of the assembly, the locking screw 18E is released to allowthe handle 18 to rotate the gear 28. The gear 28 meshing at the gearportion 30 produces rotation of the ring 30 and one end of the flexiblecable 48 attached thereto. The other end of flexible cable 48 isattached to the actuating rod 16 to produce linear movement of the same.Limits of movement are established at one end by engagement with thestop pin 40 by the spider 30B and on the other end upon engagement ofthe other stop 42 with the spider 30C.

The end of rod 16 is, of course, attached to the element to be actuated;and once its position is thus established, that position may be securedby tightening of the lock screw 18 which engages a grooved portion 24Eof the casing 24. This movement is facilitated as a result of engagementof the series of balls 36 with the circumferentially grooved portion 70Eof the teflon strip 7%.

I claim:

1. A linear actuator including a casing; a first gear; means rotatablysupporting said first gear on said casing; a second gear meshing withsaid first gear; means rotatably supporting said second gear on saidcasing; crank means secured to said second gear for rotating the same;flexible cable means having one of its ends secured to said first gearand extending partially around the same; a series of nested andapertured balls through each of which said cable means extends; guidemeans on said first gear into which the balls of said series closest tosaid one end partially extends for guiding thereby; a rod; meanssecuring the other end of said cable means to said rod; sleeve means inwhich said rod slides; means securing said sleeve to said casing; saidseries of balls extending through said guide means and into said sleevemeans; said first gear including an outer ring portion and an inner hubportion joined to said ring portion by spoke means; gear teeth on saidinner portion of said ring portion meshing with said second gear; saidflexible cable means being secured to said first gear using a threadedelement screw-threaded into a nut; said nut having a shank portionextending through said ring portion; said ring portion having a portionof its outer surface recessed to receive said threaded element and saidnut.

2. A linear actuator as set forth in claim 1 including stop meansmounted on said casing and engageable with said spoke means to limittravel of said first gear.

3. A linear actuator as set forth in claim l in which said guide meansis formed in the outer portion of said ring portion; and a flexiblestrip of anti-friction material, means maintaining said strip stationaryon said casing; and said strip being formed with an annular groovedportion into which said series of balls extends for contactingtherewith.

4. A linear actuator as set forth in claim 3 in which said casingincludes two halves; an inner annular grooved portion defined byadjacent annular portions of said casing halves; said strip beingdisposed in said inner annular grooved portion; pin means extending fromone of said casing halves into corresponding apertured portions of saidstrip.

5. A linear actuator as set forth in claim 4 in which said meanssecuring said sleeve to said casing includes a bolt extending throughsaid casing halves and through an outer notched portion of said sleevemeans.

6. A linear actuator as set forth in claim 5 in which a second boltextends through said casing halves about which said first gear rotates;said sleeve means being formed near one of its ends with an enlargedsleeve portion; said first bolt and said second bolt and said enlargedsleeve portion serving as means for securing the linear actuator on astationary support.

7. A linear actuator as set forth in claim 2 in which said stop meansincludes a pair of posts mounted on and extending from said casing andengageable with a corresponding one of two spokes for joining said ringportion to said hub portion.

8. A linear actuator as set forth in claim 1 in which said flexiblecable means has said other end thereof secured to a cylindrical elementwhich is slidably mounted in said sleeve means; and cooperatingscrewthreaded portions between said cylindrical element and said rod foradjusting their relative positions.

1. A linear actuator including a casing; a first gear; means rotatablysupporting said first gear on said casing; a second gear meshing withsaid first gear; means rotatably supporting said second gear on saidcasing; crank means secured to said second gear for rotating the same;flexible cable means having one of its ends secured to said first gearand extending partially around the same; a series of nested andapertured balls through each of which said cable means extends; guidemeans on said first gear into which the balls of said series closest tosaid one end partially extends for guiding thereby; a rod; meanssecuring the other end of said cable means to said rod; sleeve means inwhich said rod slides; means securing said sleeve to said casing; saidseries of balls extending through said guide means and into said sleevemeans; said first gear including an outer ring portion and an inner hubportion joined to said ring portion by spoke means; gear teeth on saidinner portion of said ring portion meshing with said second gear; saidflexible cable means being secured to said first gear using a threadedelement screw-threaded into a nut; said nut having a shank portionextending through said ring portion; said ring portion having a portionof its outer surface recessed to receive said threaded element and saidnut.
 2. A linear actuator as set forth in claim 1 including stop meansmounted on said casing and engageable with said spoke means to limittravel of said first gear.
 3. A linear actuator as set forth in claim 1in which said guide means is formed in the outer portion of said ringportion; and a flexible strip of anti-friction material, meansmaintaining said strip stationary on said casing; and said strip beingformed with an annular grooved portion into which said series of ballsextends for contacting therewith.
 4. A linear actuator as set forth inclaim 3 in which said casing includes two halves; an inner annulargrooved portion defined by adjacent annular portions of said casinghalves; said strip being disposed in said inner annular grooved portion;pin means extending from one of said casing halves into correspondingapertured portions of said strip.
 5. A linear actuator as set forth inclaim 4 in which said means securing said sleeve to said casing includesa bolt extending through said casing halves and through an outer notchedportion of said sleeve means.
 6. A linear actuator as set forth in claim5 in which a second bolt extends through said casing halves about whichsaid first gear rotates; said sleeve means being formed near one of itsends with an enlarged sleeve portion; said first bolt and said secondbolt and said enlarged sleeve portion serving as means for securing thelinear actuator on a stationary support.
 7. A linear actuator as setforth in claim 2 in which said stop means includes a pair of postsmounted on and extending from said casing and engageable with acorresponding one of two spokes for joining said ring portion to saidhub portion.
 8. A linear actuator as set forth in claim 1 in which saidflexible cable means has said other end thereof secured to a cylindricalelement which is slidably mounted in said sleeve means; and cooperatingscrew-threaded portions between said cylindrical element and said rodfor adjusting their relative positions.